1. Field of the Invention
The present invention generally relates to a magnetic recording/reproducing apparatus and, more particularly, to a belt driven tape running apparatus which can be applied to a magnetic recording/reproducing apparatus such as a video tape recorder (hereafter a VTR).
2. Description of the Related Art
Generally, when a user inserts a tape cassette substantially horizontally into a cassette holder at a front portion of a VTR, a front loading unit of the VTR is activated to convey the cassette holder substantially horizontally to a tape driving unit, and the tape cassette is loaded in the tape driving unit. Thereafter, a tape loading mechanism is activated to extract a tape wound in the tape cassette and wind the tape around a cylinder. An operation mode of the tape driving unit is switched to a predetermined mode to run the tape.
A demand has arisen for such a VTR to achieve higher precision of operation control for each unit while maintaining a simple arrangement, thereby improving reliability.
The above demand is directed to a tape running system for performing tape running after extracting a tape of a loaded tape cassette and winding the tap around a cylinder. That is, in the tape running system, a tape cassette is mounted on a pair of reel bases, a driving force is transmitted from a driving source to one of the reel bases via a belt transmission mechanism, and the tape is driven by a capstan and a pinch roller, thereby running the tape in correspondence with various operation modes such as tape reproduction and tape recording. Therefore, in such a tape running system, highly precise operation control is required to realize correct tape running.
In the above belt transmission mechanism, however, tensions of a driving belt differ between its forward and backward sides in a driving state. Therefore, if driving/stopping is repeated as in an intermittent slow reproduction mode, the tension at the backward side is given to the reel bases to cause a so-called "after shock" phenomenon. As a result, the reel bases are rotated in an opposite direction to vary the running position of the tape.
Therefore, in a conventional VTR, drive control of a driving motor for driving a belt transmission mechanism is electrically adjusted to correct a tape feed amount caused by the after shock phenomenon, thereby correctly running a tape.
In the arrangement in which the tape feed amount caused by the after shock phenomenon is electrically corrected, a tape feed interval is limited. Therefore, if more precise intermittent feeding is required, it becomes difficult to perform proper correction.
As described above, in the conventional magnetic recording/reproducing apparatus such as a VTR, a correctable tape feed amount caused by the after shock phenomenon is limited, and it is difficult to perform precise tape feeding. As a result, the correctable tape feed amount caused by the after shock phenomenon is limited.